This invention relates to an improved skin reservoir which contains a medicament that is topically released into the skin.
Attempts have been made to develop reservoir delivery systems which are self-adhesive and water absorbent. For example, U.S. Pat. No. 3,339,546 discloses a self-adhesive reservoir which is adapted to adhere to moist surfaces such as the moist mucosa of the oral cavity. However, one of the essential materials of this self-adhesive reservoir is an adhesive gum, preferably polyisobutylene, which is hydrophobic. Similarly, U.S. Pat. Nos. 3,598,122 and 3,598,123 disclose reservoirs which contain drugs that are continually released from an adhesive layer. These reservoirs are formed of layered materials which have drugs encapsulated in the adhesive layer. Even though the reservoirs disclosed in these prior art patents are said to be self-adhesive and are satisfactory vehicles for drugs, specific process steps are required for encapsulating or stratifying the drugs.
Hydrophilic polymers plasticized with hydric alcohol and/or water have been used for ostomy gaskets (U.S. Pat. No. 3,640,741) and for the conduction of electrical current to and from the skin (U.S. Pat. Nos. 4,125,110, 4,273,135 and 4,066,078). The polymeric formulations specifically contain organic or inorganic ions physically dissolved in the plasticizers for electron transfer. More recently, Silastic polymers (U.S. Pat. No. 4,336,243) have been used to release a nitroglycerine medicament solubilized in the plasticizer for transfer into a body through the skin. However, this matrix reservoir system tends to dry out and is not self-adherent.